<template>
  <div
    class="xtx-carousel"
    @mouseenter="stopAutoPlay"
    @mouseleave="autoPlayImg"
  >
    <ul class="carousel-body">
      <li
        class="carousel-item"
        v-for="(item, index) in list"
        :key="item.id"
        :class="{ fade: currentId === index }"
      >
        <RouterLink to="/">
          <img :src="item.imgUrl" alt="" />
        </RouterLink>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)"
      ><i class="iconfont icon-angle-left"></i
    ></a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)"
      ><i class="iconfont icon-angle-right"></i
    ></a>
    <div class="carousel-indicator">
      <span v-for="i in list.length" :key="i" @click="currentId = i - 1"></span>
    </div>
  </div>
</template>

<script>
import { onBeforeUnmount, ref, watch } from 'vue'

export default {
  name: 'XtxCarousel',
  props: {
    list: {
      type: Array,
      default: () => []
    },
    autoPlay: {
      type: Boolean,
      default: false
    }
  },
  setup (props) {
    const currentId = ref(0)
    // 按钮点击事件
    function toggle (step) {
      const _result = currentId.value + step
      if (_result > props.list.length - 1) {
        currentId.value = 0
      } else if (_result < 0) {
        currentId.value = props.list.length - 1
      } else {
        currentId.value = _result
      }
    }
    let _timer = ''
    // 监控autoplay
    watch(
      () => props.autoPlay,
      newval => {
        if (newval) {
          autoPlayImg()
        }
      },
      {
        immediate: true
      }
    )
    function autoPlayImg () {
      // console.log('play')
      clearInterval(_timer)
      _timer = setInterval(() => {
        toggle(1)
      }, 2000)
    }
    function stopAutoPlay () {
      // console.log('stop')
      clearInterval(_timer)
    }
    onBeforeUnmount(() => {
      stopAutoPlay()
    })
    return { currentId, toggle, autoPlayImg, stopAutoPlay }
  }
}
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>
